In The United States, Appellants v. The Heirs of Boisdore, the Supreme Court was asked to decide whether a French citizen who had been living in Louisiana before it became part of the United States could pass his property rights on to his heirs after he died. At issue was whether or not these property rights were protected by the Treaty of 1803 between France and the U.S., which stated that all citizens should be able to keep their possessions when they moved from one country to another. After considering both sides’ arguments, the court ruled that Boisdore's heirs did have a right to inherit his estate because he had acquired it prior to Louisiana becoming part of America and thus its protection under international law applied even though he was no longer alive at the time of judgment. This ruling established an important precedent for how foreign nationals' estates are treated within American borders and set forth guidelines for future cases involving similar issues regarding inheritance laws across different countries’ boundaries.

In the United States v. The Heirs of Boisdore, the Supreme Court was tasked with determining whether a grant issued by Spain in 1795 to Jean Baptiste Boisdore and his heirs was valid under U.S. law following Louisiana's admission into the Union as a state in 1812. The majority opinion held that it was not valid because Congress had never confirmed or recognized it, but Justice Daniel dissented from this decision on two grounds: firstly, he argued that there were no laws passed by Congress which would have invalidated such grants; secondly, he maintained that even if such laws did exist they could not be applied retroactively to pre-existing grants like those of Boisdore's since doing so would violate due process principles established in prior cases involving private property rights and vested interests. Ultimately, Justice Daniel concluded that “the title derived from [Boisdore] is good against all persons claiming under any other source” and thus should remain intact despite its lack of congressional recognition or confirmation